blob: ece314ad2ed4dfc4fc5d17ddc7f6481ecc1b07f3 [file] [log] [blame]
/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/private/SkSpinlock.h"
#include "include/private/base/SkThreadAnnotations.h"
#if 0
#include "include/private/base/SkMutex.h"
#include <execinfo.h>
#include <stdio.h>
static void debug_trace() {
void* stack[64];
int len = backtrace(stack, std::size(stack));
// As you might imagine, we can't use an SkSpinlock here...
static SkMutex lock;
{
SkAutoMutexExclusive locked(lock);
fprintf(stderr, "\n");
backtrace_symbols_fd(stack, len, 2/*stderr*/);
fprintf(stderr, "\n");
}
}
#else
static void debug_trace() {}
#endif
// Renamed from "pause" to avoid conflict with function defined in unistd.h
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
#include <emmintrin.h>
static void do_pause() { _mm_pause(); }
#else
static void do_pause() { /*spin*/ }
#endif
void SkSpinlock::contendedAcquire() {
debug_trace();
// To act as a mutex, we need an acquire barrier when we acquire the lock.
SK_POTENTIALLY_BLOCKING_REGION_BEGIN;
while (fLocked.exchange(true, std::memory_order_acquire)) {
do_pause();
}
SK_POTENTIALLY_BLOCKING_REGION_END;
}